Plane / Planes / Aircraft / Aeroplane / Airplane appreciation

I think I remember reading that helicopter generally tend to "topped" out at 200mph, the Eurocopter's 250mph doesn't seemed that much of a big deal TBH.

Helicopter airspeeds are limited, mainly, by the velocity of the rotor blades as they travel forward in each rotation. Add that forward velocity to the IAS of the helicopter and it's quite easy for the tips of the blades to go supersonic if you try to go too fast, with the accompanying aerodynamic and blade-falling-to-bits problems that causes. Shaping the tips can help, but basically, it's difficult to make a helicopter go fast.